The overall aim of this proposal is to study alcohol induced aggression and to attempt to determine the underlying neurochemistry of this behavior. The specific aims are 1) to measure ethanol induced aggressive responding in subjects with antisocial personality disorder (ASP) and matched controls, and 2) to measure baseline serotonin function in subjects with ASP and matched controls using a d-fenfluramine neuroendocrine challenge. Rationale: The association between ethanol use and violence in the general population has been well documented. Ethanol also increases aggressive responding in humans and animals under controlled laboratory conditions, but large inter-indivdual differences in this effect have been observed. Retrospective studies which examine the relationship between ethanol use and aggression find that alcoholics with Antisocial Personality Disorder (ASP) have have an earlier age of onset of drinking, and more social and occupational problems related to drinking. These inviduals have been found to have lower serotonin (5-HT) function as measured by CSF 5HIAA. Thus there is evidence linking ASP and 5-HT to aggression and ethanol. The research proposed will investigate the relationship between ASP and ethanol induced agressive responding and attempt to determine the role of 5-HT in these behaviors under controlled laboratory conditions. Preliminary results from research performed thus far finds that subjects with ASP show a significant difference in the pattern of their aggressive responding after alcohol compared to controls. ASP subjects show a dramatic increase in aggression, and non-ASP subjects show a decrease. ASP subjects, not surprisingly, reported more aggression on self report measures such as the Brown and the ROAS.